Choose your desired key. Look to the top, right box on JamStudio, then look to the top, left corner of that box. To the right of where it says "Key of G" (or other note), find an "Up" and a "Down" arrow. Select your desired key by clicking on these arrows and cycling through the available options. The chords displayed below this section will change dependent on the key you select.
Click on the name of the first chord you wish to add into the main song. Look in the top, left box of the main screen to see the song display. Choose one of the six chords underneath the name of the key to make a simple song. Generally, you will want to start on the same note as the key. For example, start on a C chord if you are in the key of C. Alternatively, start on a related minor, such as A minor in the key of C.
Continue choosing chords to fill the bars of the song. Each chord you select will be played for one bar of the piece of music. Choose a chord not listed underneath the key using the section to the right of the six main chords. Check the "Variation" box to get access to seventh chords and suspended chords.
Compose your song using minor chords wherever possible. Working minor chords into your song will make it more suitable as a slow song. Use the minors listed below the key for the simplest composition. Click on instruments you wish to include in your song from the options in the box in the bottom left hand corner. For example, click on "Guitar" to highlight the speaker icon beside it and add that instrument into the mix. Select the type of guitar you want from the options in the bottom right hand corner. For example, click "Mellow" to get a relaxed guitar sound. Choose all the instruments you wish to include in the same way.
Lower the tempo to the desired level by clicking on the "Tempo" bar in the bottom, left corner of the main screen. Click low down on the column of blue blocks to select a slow tempo or high up on it to select a high tempo. Choose as low a tempo as you wish for your slow song. The number indicates the currently selected tempo.
Press "Play" to preview your song. The "Play" button is located at the top of the bottom, left box on the main screen.